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><H1
><A
NAME="SQL-ALTERDOMAIN"
></A
>ALTER DOMAIN</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN59902"
></A
><H2
>Name</H2
>ALTER DOMAIN&nbsp;--&nbsp;   change the definition of a domain
  </DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN59907"
></A
><H2
>Synopsis</H2
><PRE
CLASS="SYNOPSIS"
>ALTER DOMAIN <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
>
    { SET DEFAULT <TT
CLASS="REPLACEABLE"
><I
>expression</I
></TT
> | DROP DEFAULT }
ALTER DOMAIN <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
>
    { SET | DROP } NOT NULL
ALTER DOMAIN <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
>
    ADD <TT
CLASS="REPLACEABLE"
><I
>domain_constraint</I
></TT
>
ALTER DOMAIN <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
>
    DROP CONSTRAINT <TT
CLASS="REPLACEABLE"
><I
>constraint_name</I
></TT
> [ RESTRICT | CASCADE ]
ALTER DOMAIN <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
>
    OWNER TO <TT
CLASS="REPLACEABLE"
><I
>new_owner</I
></TT
>
ALTER DOMAIN <TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
>
    SET SCHEMA <TT
CLASS="REPLACEABLE"
><I
>new_schema</I
></TT
></PRE
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN59920"
></A
><H2
>Description</H2
><P
>   <TT
CLASS="COMMAND"
>ALTER DOMAIN</TT
> changes the definition of an existing domain.
   There are several sub-forms:
  </P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
>SET/DROP DEFAULT</DT
><DD
><P
>      These forms set or remove the default value for a domain. Note
      that defaults only apply to subsequent <TT
CLASS="COMMAND"
>INSERT</TT
>
      commands; they do not affect rows already in a table using the domain.
     </P
></DD
><DT
>SET/DROP NOT NULL</DT
><DD
><P
>      These forms change whether a domain is marked to allow NULL
      values or to reject NULL values.  You can only <TT
CLASS="LITERAL"
>SET NOT NULL</TT
>
      when the columns using the domain contain no null values.
     </P
></DD
><DT
>ADD <TT
CLASS="REPLACEABLE"
><I
>domain_constraint</I
></TT
></DT
><DD
><P
>      This form adds a new constraint to a domain using the same syntax as
      <A
HREF="sql-createdomain.html"
>CREATE DOMAIN</A
>.
      This will only succeed if all columns using the domain satisfy the
      new constraint.
     </P
></DD
><DT
>DROP CONSTRAINT</DT
><DD
><P
>      This form drops constraints on a domain.
     </P
></DD
><DT
>OWNER</DT
><DD
><P
>      This form changes the owner of the domain to the specified user.
     </P
></DD
><DT
>SET SCHEMA</DT
><DD
><P
>      This form changes the schema of the domain.  Any constraints
      associated with the domain are moved into the new schema as well.
     </P
></DD
></DL
></DIV
><P
>   You must own the domain to use <TT
CLASS="COMMAND"
>ALTER DOMAIN</TT
>.
   To change the schema of a domain, you must also have
   <TT
CLASS="LITERAL"
>CREATE</TT
> privilege on the new schema.
   To alter the owner, you must also be a direct or indirect member of the new
   owning role, and that role must have <TT
CLASS="LITERAL"
>CREATE</TT
> privilege on
   the domain's schema.  (These restrictions enforce that altering the owner
   doesn't do anything you couldn't do by dropping and recreating the domain.
   However, a superuser can alter ownership of any domain anyway.)
  </P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN59957"
></A
><H2
>Parameters</H2
><P
>    <P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="REPLACEABLE"
><I
>name</I
></TT
></DT
><DD
><P
>        The name (possibly schema-qualified) of an existing domain to
        alter.
       </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>domain_constraint</I
></TT
></DT
><DD
><P
>        New domain constraint for the domain.
       </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>constraint_name</I
></TT
></DT
><DD
><P
>        Name of an existing constraint to drop.
       </P
></DD
><DT
><TT
CLASS="LITERAL"
>CASCADE</TT
></DT
><DD
><P
>        Automatically drop objects that depend on the constraint.
       </P
></DD
><DT
><TT
CLASS="LITERAL"
>RESTRICT</TT
></DT
><DD
><P
>        Refuse to drop the constraint if there are any dependent
        objects. This is the default behavior.
       </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>new_owner</I
></TT
></DT
><DD
><P
>        The user name of the new owner of the domain.
       </P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>new_schema</I
></TT
></DT
><DD
><P
>        The new schema for the domain.
       </P
></DD
></DL
></DIV
><P>
   </P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN59996"
></A
><H2
>Notes</H2
><P
>   Currently, <TT
CLASS="COMMAND"
>ALTER DOMAIN ADD CONSTRAINT</TT
> and
   <TT
CLASS="COMMAND"
>ALTER DOMAIN SET NOT NULL</TT
> will fail if the named domain or
   any derived domain is used within a composite-type column of any
   table in the database.  They should eventually be improved to be
   able to verify the new constraint for such nested columns.
  </P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN60001"
></A
><H2
>Examples</H2
><P
>   To add a <TT
CLASS="LITERAL"
>NOT NULL</TT
> constraint to a domain:
</P><PRE
CLASS="PROGRAMLISTING"
>ALTER DOMAIN zipcode SET NOT NULL;</PRE
><P>
   To remove a <TT
CLASS="LITERAL"
>NOT NULL</TT
> constraint from a domain:
</P><PRE
CLASS="PROGRAMLISTING"
>ALTER DOMAIN zipcode DROP NOT NULL;</PRE
><P>
  </P
><P
>   To add a check constraint to a domain:
</P><PRE
CLASS="PROGRAMLISTING"
>ALTER DOMAIN zipcode ADD CONSTRAINT zipchk CHECK (char_length(VALUE) = 5);</PRE
><P>
  </P
><P
>   To remove a check constraint from a domain:
</P><PRE
CLASS="PROGRAMLISTING"
>ALTER DOMAIN zipcode DROP CONSTRAINT zipchk;</PRE
><P>
  </P
><P
>   To move the domain into a different schema:
</P><PRE
CLASS="PROGRAMLISTING"
>ALTER DOMAIN zipcode SET SCHEMA customers;</PRE
><P></P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="SQL-ALTERDOMAIN-COMPATIBILITY"
></A
><H2
>Compatibility</H2
><P
>   <TT
CLASS="COMMAND"
>ALTER DOMAIN</TT
> conforms to the <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
>
   standard,
   except for the <TT
CLASS="LITERAL"
>OWNER</TT
> and <TT
CLASS="LITERAL"
>SET SCHEMA</TT
> variants,
   which are <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> extensions.
  </P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="SQL-ALTERDOMAIN-SEE-ALSO"
></A
><H2
>See Also</H2
><A
HREF="sql-createdomain.html"
>CREATE DOMAIN</A
>, <A
HREF="sql-dropdomain.html"
>DROP DOMAIN</A
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